This is the third article in a seven part series on altered chords. In the first part I explained that by lowering or raising a tone of a chord by a half step you can change the color and function of a chord.

Part 1 look at altered V chords, and Part 2 at altered II chords. We will continue the series by exploring various ways to alter the VI chord.

Diatonic vi

The sixth diatonic chord in a major key is a minor 7th chord. In the key of D it's Bm7. It's harmonic function is as a tonic chord, meaning that it can be felt as a place of rest, though it is much less stable and final feeling than the major tonic I. It is often used either as a passing chord along the way to II or IV, or as the target chord in a deceptive cadence.

A common progression using the VI chord is I-vi-IV-V-I, which has that classic 1950s sound:

In a deceptive cadence the VI chord can take the place of I, creating a sense of surprise but still maintaining the potential for a place of rest. In this example we have a simple I-IV-V-I progression, followed by I-IV-V-vi. You expect the vi chord to be a I, hence the deception:

In minor keys the sixth diatonic chord is a bVI major chord:

Altered VI

The more common alterations of VI in major keys include:

bVI

bVImaj7

VI major

VImaj7

VI7

Altering Each Chord Tone

As explained in the previous article, a chord is "altered" by lowering or raising one or more chord tones by a half step. Since there are four pitches in a minor 7th chord (1 b3 5 b7), that gives us four choices for tones to alter.

Here we'll go through systematically and examine the results of altering each tone of the chord.

Altering the Root

Changing the root of the VI chord is one of the most common alterations. If you lower the root to bVI and also lower the fifth of the chord, you are essentially borrowing the bVI chord from the parallel minor key.

The bVI major chord has a lot of fun potential. It can feel very sci-fi, majestic and awe-inspiring when alternated with tonic I:

bVI can also have a great smooth bluesy feel to it, often used to slide down into the 5 chord in a 12-bar blues song. All Blues is a perfect example of this use. (More advanced harmony students should note that the chord has an added b7 and is essentially a subV7 of V, rather than an altered VI, but altering the VI chord can bring us the same result.)

The first use of the bVI7 chord occurs at 0:45:

Notice that the bVI (in this case Eb7) has a strong tendency to pull down a half step. This is a very common characteristic of lowered root chords.

bVI can also have a fun quirky aspect to it as well. Because it's a major chord it still feels bright and upbeat, but something feels perhaps just a little off:

If you lower the root without changing the fifth, you end up with an augmented chord, or bVI+. If you use bVI+7 you have a similar result as in All Blues, with a tendency to pull down into V7:

If instead you use a major 7th, bVI+maj7, you get a very dissonant sound. Notice that the tonic I chord still has a presence since it makes up the upper 3 notes of the chord:

The other way to change the root would be to raise it, but in this case you would be creating a I7 chord in first inversion:

As we'll also see in a moment with raising the fifth, since we've changed to a different chord this doesn't really count as an alteration.

Altering the Fifth

Rather than adding an interesting spice, raising the fifth of the minor vi chord actually changes the function of the chord entirely.

As you can see, raising the fifth changes the chord from Am to F in first inversion (with the third in the bass). Unless you are purposefully looking for a way to change the role of the chord, you can't make this alteration without losing your VI chord entirely. For this reason raising the fifth is not a practical option.

Lowering the fifth creates a more troublesome chord, a minor7b5 chord (sometimes called half-diminished 7th). There are a ton of different way to interpret this chord in context, one that makes sense to me is to think of it as IV7 without the root.

Just compare the progression I7-vim7b5-I7 with I7-IV7-I7 and you'll notice that they are very much the same as far as function is concerned:

The seventh of the vim7b5 chord can be thought of as the ninth of the IV7.

Altering the Third

Lowering the third creates a sus2 chord, which is typically a very open and neutral sounding chord. If used in the right context however, VIsus2 can actually retain it's minor character because the missing minor third is still the tonic of the key:

The open sound has a certain reflective quality while still retaining some sadness.

Raising the third, creating a VI major chord, can have a similar "sci-fi" effect as using the bVI major chord. Just listen to the "Rebel Fanfare" theme from Star Wars using parallel major triads:

Altering the Seventh

Raising the seventh to create a minor major seventh chord gives us a pretty dissonant sound:

Although it may be an interesting dissonant choice, it is not something that shows up very often in the context of a VI chord.

Lowering the seventh (which you'll remember is already b7) to create a minor sixth chord is a much more interesting sound in my opinion. It's a far more ambiguous chord that can resolve smoothly in a lot of different ways. Here are just two examples of how vi6 can be used as a transition chord for modulation:

Conclusion

Similar to altering the II chord, altering the chord tones of VI can greatly affect the chord's tendencies in a progression. The possibilities for altering VI also open up a wide palette of interesting harmonies that can still function in an otherwise diatonic progression.

Next up in the series will be the altered III chord.

Please leave your comments and questions below and we will continue to discuss them in the future parts of the altered chord series.